The Regulation of Geoengineering - Science and Technology Committee Contents

2 Categories of geoengineering

Introduction

16. This chapter examines what technologies and techniques
could be classed as geoengineering and what can and should be
regulated. As we explained in the previous chapter, we use the
term "geoengineering" to describe activities specifically
and deliberately designed to effect a change in the global climate
with the aim of minimising or reversing anthropogenic climate
change.[27] We are examining
geoengineering exclusively in relation to climate change. Our
starting point is again our earlier Report, Engineering: turning
ideas into reality[28]
along with the Royal Society's report, Geoengineering the climate:
science, governance and uncertainty.[29]

Definition of geoengineering

17. Geoengineering is not, however, a monolithic
subject.[30] Geoengineering
methods are "diverse and vary greatly in terms of their technological
characteristics and possible consequences".[31]
They can beand were by those who submitted evidence to
usclassified into two main groups: Carbon Dioxide Removal
(CDR) techniques; and Solar Radiation Management (SRM) techniques.

a) techniques for enhancing natural carbon sinks
(the oceans, the forests, rocks and soils); and

b) sequestration of carbon dioxide from the atmosphere
("atmospheric scrubbing") by chemical means, with the
captured carbon deposited in the deep ocean or in geological structures.

Examples of CDR techniques

Bioenergy with carbon dioxide capture and sequestration (BECS) Biomass may be harvested and used as fuel, with capture and sequestration of the resulting carbon dioxide; for example, the use of biomass to make hydrogen or electricity and sequester the resulting carbon dioxide in geological formations.[32]

Biomass and biochar As vegetation grows it removes large quantities of carbon from the atmosphere during photosynthesis. When the organisms die and decompose, most of the carbon they stored is returned to the atmosphere. There are several ways in which the growth of biomass may be harnessed to slow the increase in atmospheric carbon dioxidefor instance, Biomass may be harvested and sequestered as organic material, for example, by burying trees or crop wastes, or as charcoal ("biochar").[33]

Enhanced weathering (land and ocean-based methods) Carbon dioxide is naturally removed from the atmosphere over many thousands of years by processes involving the weathering (dissolution) of carbonate and silicate rocks. Silicate minerals form the most common rocks on Earth, and they react with carbon dioxide to form carbonates (thereby consuming carbon dioxide).[34]

Ocean fertilisation Phytoplankton take up carbon dioxide and fix it as biomass. When the organisms die, a small fraction of this "captured" carbon sinks into the deep ocean. Proponents of ocean fertilisation schemes have argued that by fertilising the ocean it may be possible to increase phytoplankton growth and associated carbon "removal". Ocean fertilisation schemes involve the addition of nutrients to the ocean (soluble iron, for example), or the redistribution of nutrients extant in the deeper ocean to increase productivity (such as through ocean pipes).[35]

Ocean N and P fertilisation Over the majority of the open oceans the "limiting nutrient" is thought to be nitrogen. One suggestion therefore has been to add a source of fixed nitrogen (N) such as urea as an ocean fertiliser. Phosphate (P) is also close to limiting over much of the ocean.[36]

19. The table below, which draws from the Royal Society's report,
compares the cost and environmental impact of CDR methods.[37]

Technique

Cost

Impact of anticipated environmental effects

Risk of unanticipated environmental effects

Land use and afforestation

Low

Low

Low

Biomass with carbon sequestration (BECS)

Medium

Medium

Medium

Biomass and biochar

Medium

Medium

Medium

Enhanced weathering on land

Medium

Medium

Low

Enhanced weatheringincreasing ocean alkalinity

Medium

Medium

Medium

Chemical air capture and carbon sequestration

High

Low

Low

Ocean fertilisation

Low

Medium

High

Ocean N and P fertilisation

Medium

Medium

High

SOLAR RADIATION MANAGEMENT (SRM)

20. The second category of climate geoengineering methods aims
to offset greenhouse warming by reducing the incidence and absorption
of incoming solar (short-wave) radiation.[38]
Proposals in this category include space-based shades or mirrors
to block a portion of incoming solar radiation; and ways of increasing
the Earth's albedo (that is, its surface reflectivity of the sun's
radiation) by increasing cloud cover, whitening clouds or placing
reflective particles or balloons into the stratosphere.[39]

Examples of SRM techniques

White roof methods and brightening of human settlements The purpose is to increase the reflectivity of the built environment by painting roofs, roads and pavements bright reflective "white". This would be most effective in sunny regions and during summertime where there might also be co-benefits through savings in air-conditioning.[40]

More reflective crop varieties and grasslands Land plants tend to absorb strongly in the visible photosynthetically active part of the solar spectrum, but are highly reflective in the near infrared frequencies. However, the albedo of plant canopies can vary significantly between different plant types and varieties, due to differences in basic leaf spectral properties, morphology and canopy structure. It may therefore be possible to increase significantly the albedo of vegetated surfaces through careful choice of crop and grassland species and varieties.[41]

Cloud Albedo It has been proposed that the Earth could be cooled by whitening clouds over parts of the ocean.[42]

Aerosol injection Large volcano eruptions result in the mass injection of sulphate particlesformed from the emitted sulphur dioxideinto the stratosphere. As these aerosols reflect solar radiation back to space, or themselves absorb heat, mass eruptions result in a cooling of the lower atmosphere. The eruption of Mount Tambora in present day Indonesia, for example, was thought to have produced the "year without a summer" in 1816. In the 1970s, Professor Budyko proposed that "artificial volcanoes" be geoengineered. That is, that sulphate aerosols be injected into the stratosphere to mimic the cooling effect caused by these "super-eruptions".[43]

Space mirrors Positioning a superfine reflective mesh of aluminium threads in space between the Earth and the Sun was proposed in 1997 by Dr Lowell Wood and Professor Edward Teller to reduce the amount of sunlight that reaches the Earth. It has been estimated that a 1% reduction in solar radiation would require approximately 1.5 million square kilometres of mirrors made of a reflective mesh.[44]

21. The table below, which again draws from the Royal Society's
report, compares the cost and environmental impact of SRM methods.[45]

22. The fundamental difference between CDR and SRM is that carbon
sequestration addresses the root issuethat is, the concentration
of carbon dioxidewhile solar reflection "treats the
symptom"that is, global warming.[48]
The Sustainability Council of New Zealand pointed out that problems
arising from this include:

reflection does not address the acidification of oceans that
results from excess carbon dioxide in the atmosphere being absorbed
by the sea;

schemes that inject particles into the atmosphere
are likely to alter the distribution of rainfall and also cause
some reduction in the global quantity of rainfall; and

many reflection techniques will need to be replenished
constantly over their lifetime and, if this is not kept up, extremely
rapid warming could ensue.[49]

23. The other difference is that some SRM techniques
could substantially influence the climate within months but, as
Dr Blackstock pointed out, with "much greater uncertainty
about the net climatic effects".[50]
Natural experiments caused by volcanoes have demonstrated the
rapid impact potential of SRM, and recent reviews have shown such
schemes should be technically simple to deploy at low cost relative
to mitigation. But, as Dr Blackstock noted, these reviews also
stressed that SRM would "at best unevenly ameliorate regional
climatic change, and may generate serious unintended consequences.
For example, SRM could produce droughts with severe implications
for regional and global food production, and delay the recovery
of the ozone layer by decades, while doing almost nothing to address
ocean acidification."[51]

WEATHER MODIFICATION TECHNIQUES

24. While there was a measure of debate that someCDR,
in particulartechnologies fell within the definition of
geoengineering, there was greater disagreement about weather modification
techniques should be included. The Action Group on Erosion, Technology
and Concentration (ETC Group) considered that geoengineering should
also encompass weather modification techniques such as hurricane
suppression and cloud seeding.[52]
Cloud seeding causes precipitation by introducing substances into
cumulus clouds that cause condensation. Most seeding uses silver
iodide, but dry ice (that is, solid carbon dioxide), propane,
and salt are also used.[53]

25. These techniques are in use to precipitate rain
and to suppress precipitation and hail.[54]
Dr James Lee, from the American University, Washington DC, pointed
out in his memorandum that cloud seeding was first scientifically
demonstrated in 1946[55]
and "is a geoengineering tool that is widely used by more
than 30 countries" and that with climate change, fresh water
resources will be in decline in many parts of the world and one
"result may be an increase in the use of cloud seeding".[56]
He cited the example of China, whose:

cloud seeding program is the largest in the
world, using it to make rain, prevent hailstorms, contribute to
firefighting, and to counteract dust storms. On New Year's Day
in 1997, cloud seeding made snow in Beijing, for probably no other
reason than popular enjoyment. During the 2008 Olympics, China
extensively used cloud seeding to improve air quality. China sees
cloud seeding as part of a larger strategy to lower summer temperatures
and save energy.[57]

26. Dr Lee drew a distinction between climate change
and weather:

since cloud seeding is more likely to affect
the latter. Weather is a state of the atmosphere over the short-term
and more likely at specific points and places. Climate is a long-term
phenomenon expressed as average weather patterns over a long period.
Cloud seeding could affect climate when carried out over a long
period. Key measures of weather and climate are precipitation
and temperature.[58]

27. Since 1977, cloud seeding and environmental techniques
have been subject to international regulation. In 1977 countries
agreed to the "Convention on the Prohibition of Military
or Any Other Hostile Use of Environmental Modification Techniques"
(ENMOD). The treaty, as well as forbidding the use of environmental
modification techniques in hostile circumstances, supported the
use of weather modification for peaceful purposes. A re-confirmation
of the ENMOD principles occurred at the Framework Convention on
Climate Change (UNFCCC) and the 1992 Earth Summit in Rio de Janeiro.[59]
Dr Lee pointed out that most techniques covered by the ENMOD treaty
were "quite speculative"for example, causing
earthquakes or tsunamis which was far beyond the capacity of current
technologybut that cloud seeding was a technology that
was often used.[60]

28. At the oral evidence session we asked whether
weather-changing techniques such as cloud seeding should be considered
to be geoengineering. Mr Virgoe, Dr Blackstock and Professor Keith
were clear that they should not.[61]
Mr Virgoe considered that "one of the criteria [...] for
geoengineering is that the effect needs to be at a global level,
and cloud seeding is a weather modification technique."[62]
Weather modifications such as cloud seeding which affect the weather
for no longer than a season, in our view, do not fall within the
definition of geoengineering. Moreover, these techniques are regulated
by international conventions, ENMOD and UNFCCC. We conclude
that weather techniques such as cloud seeding should not be included
within the definition of geoengineering used for the purposes
of activities designed to effect a change in the global climate
with the aim of minimising or reversing anthropogenic climate
change.

CONCLUSIONS ON DEFINITION

29. We have set out the techniques that fall within
CDR and SRM in some detail to show that there is a "very
wide range of geoengineering methods, with diverse characteristics,
methods of action and potential side effects".[63]
John Virgoe, an expert in geoengineering governance based in Australia
and who has conducted research into geoengineering governance
and regulation, was of the view that CDR and SRM are

so different in nature and implications that
it is questionable whether it is helpful to describe both as geoengineering.
Broadly speaking, the former might form an element within a package
along with mitigation and adaptation [to climate change], while
the latter might be deployed as an emergency response in the event
of highly disruptive climate change.[64]

Dr Blackstock shared his view that SRM was "unsuitable
as an alternative to mitigation".[65]

30. Taking the CDR technologies as a whole, it is
clear that the risk of a negative impact on the environment is
less than those in the SRM category. But, as the Royal Society
pointed out, ecosystem-based methods, such as ocean fertilisationa
CDR technologycarries the risk of having "much greater
potential for negative and trans-boundary side effects".[66]
As Sir David King put it: "as soon as we move into capture
from the oceans [...] we are dealing with an issue of long range
pollution and impact problems, so cross-boundary problems".[67]
On the other hand, painting roofs whitean SRM techniquewould
have little adverse effect or consequences across national boundaries.
In our view, geoengineering as currently defined covers such
a range of Carbon Dioxide Removal (CDR) and Solar Radiation Management
(SRM) technologies and techniques that any regulatory framework
for geoengineering cannot be uniform. As the Government put
it, to formulate an overarching governance framework covering
all geoengineering research and deployment "will be challenging".[68]
In our view, it is neither practicable nor desirable.

Conclusions on grading for the
purposes of regulation

31. A system to differentiate and grade geoengineering
techniques is required. As Dr Jason Blackstock put it:

When we think of developing regulatory structures
for what we class as geoengineering, our primary concern should
be about how large is the transboundary impact and how soon will
that transboundary impact manifest.[69]

In more detail the Royal Society suggested that the
fundamental criterion in relation to governance of geoengineering
was whether, and to what extent, the techniques involved:

a) trans-boundary effectsother than the
removal of greenhouse gases from the atmosphere;

b) dispersal of potentially hazardous materials
in the environment; and

32. Professor Keith preferred an approach based on
leverage, which we understand to be large effect on the climate
for a relatively small amount of resources, and timescale.[71]
Mr Virgoe added that as well as environmental risks there were
risks of things going wrong or risks of unintended side effects
and that there "is clearly a risk that the techniques do
not work and there are also risks around things like legal issues
and liability".[72]

33. We consider that geoengineering as currently
used is a useful portmanteau definition encompassing CDR and SMR
techniques but cannot be used as the basis for a single regulatory
regime. In our view the criteria suggested by the Royal Society
provide a sound basis for building a grading system for geoengineering
techniques for the purposes of regulation. They are intelligible
and likely to command support. Other criteria such as leverage
and risk could be included, though we would be concerned if the
criteria proliferated or were drawn so widely as to bring techniques
unnecessarily within tight regulatory control. We conclude
that geoengineering techniques should be graded according to factors
such as trans-boundary effect, the dispersal of potentially hazardous
materials in the environment and the direct effect on ecosystems.
The regulatory regimes for geoengineering should then be tailored
accordingly. Those techniques scoring low against the criteria
should be subject to no additional regulation to that already
in place, while those scoring high would be subject to additional
controls. So for example, at the low end of the scale are
artificial trees and at the high end is the release of large quantities
of aerosols into the atmosphere.